1. Field of the Invention
The invention relates to an antifriction bearing for a magnetic resonance tomography apparatus.
2. Description of the Prior Art
Many components of a magnetic resonance tomography apparatus should be as nonmagnetic as possible so that magnetic fields produced for a magnetic resonance examination do not have an additional magnetic field superimposed thereon. Consequently, for the guiding rollers of the patient bed in a magnetic resonance imaging apparatus, nonmagnetic antifriction bearings are used which have rolling members produced from ceramic and which have inner and outer rings, between which the rolling members roll, produced from nonmagnetic and hardened steel. However, such antifriction bearings are expensive to produce. Nonmagnetic antifriction bearings suitable for magnetic resonance systems are produced, for example, by INA Wälzlager Schaeffler KG, as described in technical product information TPI 41, published in April 1995.
An example of, guiding rollers for conveying engineering is described on page 40 of the main catalog 94/96 of the Räder-Vogel wheel and roller factory, Sperlsdeicher Weg 19-23, 21109 Hamburg. The guiding rollers are fabricated from a special material and surrounded by a special ballbearing.
Moreover, a guiding roller for vehicle doors is disclosed in DE 1 892 000 U. A ballbearing is press fit in the guiding roller consisting of plastic.